During routine anatomical dissection a rare case of a flexor digitorum accessorius longus muscle was observed. This muscle arose with a well-formed muscular belly from the lower part of the lateral intermuscular septum, and then passed obliquely downward and medially deep to the calcaneal tendon in the canal of the flexor hallucis longus. In the sole region the aberrant muscle prolonged in a thin tendon that divided into two parts: superficial and deep. The superficial part attached to the tendon of the flexor digitorum longus for the second toe; the deep part of the tendon joined the tendon of the quadratus plantae and also an additional portion of the flexor hallucis longus tendon to the second toe. The possible clinical implications of this muscle in practical surgery and also in imaging radiology are reviewed.
